Drilling-bit



.G. NYMANNING.

DRILLING BIT. APPLICATION FILED JAN. 9, 1920.

Patented A g- 31; 1920 \9' I 4 I I I GEORGE NYMANNING, OF LOS ANGELES, CALIFORNIA.

nnILtrne-BIT.

To all whom it may concern:

Be it known that I, GEORGE NYMANNING, a citizen of the. United States, residing at Los Angeles, in the county of LOs Angeles and State of California, have invented new and useful Improvements in Drilling-Bits, of which the following is a specification.

This invention relates to rotary drilling bits and has for its object to provide an im-, proved bit to facilitate cutting operations, and further to provide a bit that may be readily sharpened by the usual facilities convenient at a well instead of having to transport the bit to a remote repair shop or plant; and further to provide a bit of this type of integralco'nstruction, thus avoiding the possibility of losing separate parts and causing serious trouble as occurs when the tool. is made in sections. Another object of the invention is to. provide a bit of the fishtail character that is economical in cost of construction and in the quantity of material utilized. The invention consists of the construction and details, an embodiment of Which is illustrated in the accompanying drawing and described and claimed herein.

Figure 1 is a side elevation of the bit.

Fig. 2' is an edge elevation of the bit looking toward the right edge of Fig. 1.

Fig. '3 is a transverse section on line 3-3 of Fig. 1.

The bit is designed to .be readily forged out of a single piece of material of suitable dimensions according to the size of the bit to be produced, and is preferably so constructed and shaped that it may be readily sharpened after a period of use on an anvil such as may commonly be found around a well structure. The tool comprises an up per body portion 2 termed the butt, more or less cylindrical in form and having 'a transverse shoulder or end 3 from which proj ects the usual threaded shank 4 to .receive a driving rod operative by any suitable rotary drill head arranged at the well works. The

body of the tool, while it is given the general outline of the wellknown form of fishtail tool, is in the present case bifurcated to form substantially duplicate downwardly extending blades 5 and 6 diverging from the crotch 7 of the butt 2 outwardly toward their lower ends, as clearly shown in Fig. 2. The blades, while they decrease in thickness from their upper portions toward their lower ends, increase in width so that their side faces near the ends are wider than the Specification of Letters Patent.

Application filed January 9, 1920. Serial No. 350,464.

- other and a threaded shank Patented Au 31, 1920.

upper portions of the side faces. Thus by the width of the blades 5 and 6 and by their ofi'settlng w1t l1 respect to the longitudinal axis of the bit as clearly shown in Fig. 3,

the diameter of the h6le being drilled is de-' core at the bottom of the hole during the .drilling in the manner common to -the fishtail bit. The lower portions of the blades 5 and 6 ma be of concavo convex form as shown in ig. 3so as to produce a cutting effect at its points 10--10 Fig. 3, after the manner of a plowshare.

' These cutting points may be deflected inwardly to form lips 11 shown in Fig. 2.

A further improvement in tools of this general type is secured by terminating the Water holes 12 leading in through the threaded shank 4 at the top of the space formed between the upper ends of the blades 5-6 so that the water supplied during drilling is forced directly against the cutting blades and the washing of the hole is accelerated.

Various changes may be made without departing from the spirit of my invention, as

claimed.

I claim. 7

1. A fish-tail, rotary cutting bit comprising a butt or head portion with downwardly extending laterally spaced ri id cutting blades, the blades relatively oset to each extending upwardly from said butt.

2. A fish-tail, rotary cutting bit comprising a butt or head portion with downwardly extending laterally spaced rigid. cutting blades, the bladesrelatively offset to each other; the lower edges of the blades inclin ing upwardly and inwardly to form an obtuse angle relatively.

" 3. A fish-tail, rotary cutting bit comprising a butt or head portion with downwardly extending laterally spaced ri id cutting blades, the blades relatively 0 set to each other; the lower ends of the blades-being of concavo convex cross section, the lower edges of the blades inclining upwardly and inwardly to form an obtuse angle relatively.

\ 4. A fish-tail, rotary cutting bit comprising a butt or head portion with downwardly extending laterally spaced rigid cutting blades, the blades relatively ofiset to each other; the butt of the bit being provided with water holes terminating between the upper spaced ends of the blades.

5. A fish-tail rotary cutting bit comprising a butt, blades extending downwardly from said butt and spaced laterally and offset relatively to each other, a threaded shank 10 extending upwardly from said butt, said shank and said butt being provided with water holes extending therethrough and terminating at their lower ends between the upper spaced ends of said blades. '15

In testimony whereof I have signed my name to this specification.

GEO. NYMANNING. 

